Ringer apparatus



April 23; 1935. w. H. EDWARDS Alf 1,993,536

RINGER APPARATUS Filed March 4, 1932 PoZe mece azw-P Sta a screw and Ematw e Gal g INVENTORS W EEdw-azmk B JJB. Gnu/m c ATTORNEY Patented Apr. 23, 1935 {PATENT OFFICE RINGER .APPARArus William H. Edwards, Great Neck, and some. Grant, Brooklyn, N. Y., assignors to American Telephone and Telegraplifiompany, a corporation of New York Application March 4, 19.32,..Serial No. 596,808,

1- claim: 177- 7 by the ringer operation. However, there have This invention relates to signaling systems and more particularly to arrangements for producing improved-acoustical effects from. the signaling devices. utilized in such systems.

One of. the primary objects. of the. improved signaling arrangements ofthe inventionconsists in providingiinging signals with an improved and more pleasant tone and lower volume of .sound outputin. instances where the. maximum ringing. volume of certain existing types of equipmentis .not necessary. A need. has-been felt for such a. type of signals in. furnishing telephone service, for example, for residence. extension stations and relatively quiet business. offices. The signaling. arrangements of the invention will produce anacoustic effect far more pleasant than former arrangements. in; that the pleasing after-tones of the gongs will be preserved, harsh and; unpleasant inharmonic frequencies which might cause discordant eifects will be eliminated, and extraneous. noises such as poundin or. hammering, effects will be avoided. Other objects and; features of. the invention willappear -more fully from. the, detailed description thereof. hereinafter given.

' Heretofore, when. a demand existed for .a' signal with low volume, damped ringer gongs have been used which not only reduces the volume. of sound output but damps the vibration after the clapper strikes the. gong- This: results ii'relimihating the pleasing afteretones of the :gongs. Another method. utilized to reduce volume using the same size. gongs, is to-use a. metal clapper but impartto it a smaller striking force. This can be accomplished by reducing the mass. of the clapper assembly or reducing its amplitude. of vibration. However, with such a method although the eirectivevolume is vreduced, the harsh and unpleasant inharmonic frequencies. produced in the gongsby the: metal-to-metal. contact are not eliminated and the resultant tone is-not improved.

The arrangements of the invention make use of non-metallic clapper material. This. elimi- I nates the metallic contact sound and in addition generates fewer inharmonic frequencies.

It pointed out that anon-metallicclapper used in conjunction with regular ringer gongs will produce a signal of the clesi-r-ed sound characteristics providing: there are no other sounds produced above not heretofore been available ringer structures which do not. produce. considerable extraneous noise by the armature striking the. pole pieces or backstop screw except the harmonic. type of ringer when so adjusted that the armature does not strike. thecores... However, aregular 20. cycle harmonic ringer adjusted .as pointed. out

' has an even. more. objectionable characteristic in that the clapper. rests. against the gongs for an appreciable intervalafter .ir'npact, thereby deadening certain. of the vibrations and. producing a hammering effect. Furthermore, with the typesofringers heretofore available the pounding. sounds'produced by the striking of the clapper. against the gongs are. transmitted through the ringer mounting to the subscribers set. and the-surface to which it is attached and v are apt to- .be very. objectionable.

It is theprimary object of the arrangements of the invention toprovide a ringer which will produce an improved acoustical effect and which eliminates theunpleasant effects of ringers Iheretoiore. utilized. To accomplish the desired. result the. ringer of the invention utilizes anon-metallic. clapper and includes among its characteristics the following features- The clapper mechanism will be so arranged as to strike thegongs. and

.move away with 'sufiicient rapidity toavoid damping the vibrations of the .gong. The. armature iven.

. The. invention may. be more fully understood.

from the following description together with the accompanying drawing in the Figures .1 to '7. of

which the invention is illustrated- In Fig. -l is shown diagrammatically a ringer embodying the ieatures of the invention.. Fig. 2 shows in detail a portion of the arrangements of Fig. I. Fig. 3

is a modification of the arrangements of the invention asapplied to a ringer of the tuned reed or harmonic type. Fig. 4 isa. side elevation of the arrangements ofFig. 3.. 7 Figs. 5130 '7 inclusive are assembly will. be constructed so as to be decelgraphic illustrations of the motions of the armatures and clappers of the ringers under various conditions. Similar reference characters have been utilized to denote like parts in all of the figures.

In Fig. l is shown a ringer embodying the arrangements of the invention. The ringer comprises the gongs I and 2, the electromagnets 3 and 4 having pole pieces 5 and 6 respectively. A clapper rod 1 is shown attached to armature 9. The clapper rod would have at its extremity a clapper 8 of non-metallic material such as raw hide or wood. The ringer would be attached to the subscribers set M by the ringer frame l2 and by the flexible or elastic Washers l3 and I5. The armature arrangement is shown in more detail in Fig. 2. The armature will be provided with an elastic stop between itself and the pole piece and backstop screw. This elastic stop may consist of metallic springs, elastic cords, elastic materials, or other arrangements. The arrangement shown is an elastic material ID, such as rubber. special fastening is necessary as the rubber tube In is normally smaller than the armature and is installed by stretching it. The wall thickness of the elastic material is such that the material replaces the present stop pin or non-freezing disc on the under surface of the armature. A stop spring I I, which may be of copper, is provided between the stop screw and the elastic material In to prevent possible sticking inasmuch as the biasing spring I5 normally holds the armature against this stop. While this feature may introduce a metallic contact, nevertheless due to the flexible material under the spring II the sound at impact is not objectionable. While the elastic material has been shown as mounted on the extremity of the armature, nevertheless it may be mounted in various other ways, such as on both ends of the armature, on the armature and clapper assembly, or on the frame or other parts of the ringer.

In Figs. 5 to 7 inclusive are shown curves graphically representing ringer clapper and armature motion under various conditions. In Fig. 5 curve B shows armature motion for ringers of the prior art. In Fig. 6 curve D shows armature motion for a ringer of the invention equipped with elastic stops. It will be noted from curve B that the motion of a regular armature with regular metallic stops has an approximately rectangular characteristic indicating a very rapid acceleration and deceleration. By using elastic stops for the armature as in the arrangements of the invention, the armature motion is such that it more nearly approaches a sinusoidal characteristic, as shown by the curve D. By decelerating the armature at a slower rate near its limits of travel, the sudden impact which ordinarily causes sound is avoided and in addition, the energy which is dissipated at impactis stored in the elastic material and partially regained when the armature starts to move in the opposite direction. As has been heretofore pointed out one of the features of the arrangements of the invention consists in gradual rather than very rapid deceleration of the armature assembly in order to avoid noises of impact.

The transmission of energy from the ringer to the subscribers set, or to the article or desk, to which it is mounted is apt to produce a hammering sound. In accordance with the arrangements of the invention these hammering sounds can be eliminated or greatly reduced by providing a flexible ringer mounting in Wh Q Vibrations are rapidly damped out. This allows the shocks generated by the ringer operation to be absorbed by the mounting and the energy dissipated without transmitting it to the set. Ac-

cordingly, the ringer is mounted with flexible or elastic washers, such as l3 and I5, between the ringer frame l2 and the subscribers set M. This elastic insulation may take the form of rubber washers as shown or may consist of coil spring or other flexible supports. In general the greater where B is proportional to the energy transmitted and r is the period of natural vibration ri is the period of the disturbing force, and y is a damping factor. The maximum value B may have its unity and corresponds to a very stiff mounting which would have a short period of vibration, 1 being 0. When the natural frequency of vibration is low, 1' is large and B which is proportional to the energy transmitted is small.

A modified form of the ringing arrangements ofthe invention is shown in Figs. 3 and 4 in which a tuned reed type ringer is illustrated. Fig. 3 shows a front view of the ringer. Fig. 4 shows a side elevation of Fig. 3. This ringer comprises the gongs 20 and 2|, the non-metallic clapper 23 and the clapper rod 22. The clapper rod 22 is connected to a reed-mounted armature assembly 26 which is controlled by the electromagnets 24 and 25. In Fig. 4 the reed 21 is ailixed to the armature 26 by being clamped to the portions 28 thereof. The reed 21 is fastened by the mem-- bers 29 to the cores of armatures of magnets 24 and 25 as shown in Fig. 3. As in the arrangements shown in Fig. 1, the ringer of Fig. 3 would be connected to the subscribers set through a flexible or elastic mounting which has not been shown. The reed mounted armature and clapper assembly is mechanically tuned. The ringer is adjusted in such a manner that the armature does not strike the pole pieces and hence armature chatter noises are eliminated entirely. To avoid a pounding noise due to the clapper damping the vibrations of the gongs by remaining too long in contact with them, the ringer of the invention will be tuned mechanically to a sufficiently high frequency, such for example as 50 cycles, to produce a clean ring, but will be tuned electrically to the ringing frequency, such for example as 20 cycles. Thus the major motion of the clapper is at ringing frequency but when the gong is struck, a minor vibration is set up at the higher frequency and prevents the clapper from remaining against the gong. A graph of the clapper motion is shown in Fig. '7. It will be noted that the super-imposition of the natural period of vibration on the major movement of the clapper will cause the clapper to move away from the gongs as at points LM and L'--M' on the curve with sufficient rapidity to avoid damping the vibrations of the gongs.

While the invention has been disclosed as embodied in certain specific arrangements which are deemed desirable it is understood that it is capable of embodiment in many and other widely varied forms without departing from the spirit of the invention as defined by the appended claim.

What is claimed is: a

A ringer of the reed mounted armature type comprising a gong, a clapper rod and a clapper for actuating said gong; and an armature mounted on a reed and connected to said clapper rod,

said armature and rod assembly being mechanically tuned tohave a frequency of vibration sufliciently higher than the major vibrating movement imparted thereto by the ringing currents that the clapper will strike the gong and move away rapidly to avoid damping the vibrations of the gong.

WILLIAM H. EDWARDS.

JOHN R. GRANT. 

